SVG LITHOGRAPHY SYSTEMS, INC. (SVGL) on DUV from the 10-K 12/30/97
SVGL designs, manufactures, markets and services advanced
photolithography exposure systems. Photolithography is one of the most critical
and expensive steps in integrated circuit fabrication, representing
approximately one-third or more of the fabrication cost. Consequently,
integrated circuit manufacturers focus on obtaining advanced photolithography
equipment to help them produce critical layers for increasingly complex devices
reliably, efficiently and cost-effectively.
In the photolithography step of the fabrication process, the integrated
circuit patterns are projected through masks, or reticles, onto the silicon
wafers. As semiconductors have become more complex, the patterns have become
finer, with line widths as narrow as 0.25 micron (approximately 10 millionths of
an inch) and below in many of today's more advanced integrated circuits. As the
patterns become finer, photolithography exposure systems must be capable of
projecting the patterns through the masks with ever finer resolution. The
resolution
capability of a photolithography exposure system is a function of numerical
aperture (a measure of its light gathering characteristics) and the wavelength
of the light used in exposure. With the advancement of photolithography
technology has come a trend toward the reduction in wavelength from G-line (436
nanometer) to I-line (365 nanometer) to Deep UV (248 and 193 nanometer) and the
increase in numerical aperture from 0.2 to 0.6.
Historically, there have been two major approaches to photolithography
exposure systems: full field scanning projection aligners ("scanners") and
refractive steppers ("steppers). Scanners project a full scale mask image onto a
moving full wafer, while steppers sequentially expose a small section of a wafer
in a stepped sequence of exposures, but do so by reducing the size of a mask
image by several fold (typically 5 times). Thus, scanners offer large exposure
fields while steppers offer masks that are easier to make and have a lower cost.
These strengths are combined in the step and scan system, a technology pioneered
by SVGL.
Micrascan. The Company believes that its Micrascan photolithography step
and scan exposure system provides the increased resolution required for current
advanced logic and memory devices and for succeeding generations of complex,
fine geometry integrated circuits through its use of Deep UV lamp or laser light
source and unique projection optics design. Micrascan overcomes the line-width
limitations of steppers over a large exposure field by combining the elements of
both steppers and scanners into the Micrascan's step and scan technology.*
The Micrascan combines advantages of scanning projection aligners and
steppers by scanning a portion of the wafer, then "stepping" to another portion
of the wafer and repeating the process as necessary. Each scan has the
capability to expose a large segment of the wafer. The large exposure field
enables Micrascan to fabricate larger devices in a single scan than steppers,
thus avoiding the necessity of "stitching" a circuit together through two
different exposures. In addition, Micrascan continuously modifies the position
of the wafer surface during the scan, using its on-the-fly focus system to keep
the wafer in the optimal focal plane, thus providing a larger usable depth of
focus. The larger the usable depth of focus field is, the more tolerant of
variations in the wafer surface the equipment will be. The Company believes
Micrascan's greater tolerance of wafer surface variations can reduce the number
of defective devices on a wafer, thereby contributing to higher yields.* It
further believes that scanning across the field instead of exposing the entire
field at one time also enables Micrascan to achieve greater uniformity of
resolution across the entire exposure field and contributes to higher yields of
faster devices.*
The Company believes that SVGL has substantial technological expertise
and process knowledge in developing Deep UV step and scan photolithography
systems. SVGL has developed internal capability to design and fabricate optical
lenses, mirrors and coatings. This includes a combination of purchased and
proprietary optical metrology using phase measuring interferometry to precisely
measure and test the optical elements it produces. Micrascan incorporates both
mirrors and lenses in its optical system, which the Company believes allows for
an optical projection system that is less sensitive to environmental variants
and accommodates the use of light sources with broader spectral bandwidth (than
refractive optics), with the additional benefits of reduced running cost and
increased reliability.*
In addition to the optical system technology described above, SVGL has
developed certain proprietary mechanical systems incorporated in the Micrascan
to control the position of the wafer and the reticules prior to and during the
wafer exposure step. The Company believes that these servo controlled systems
contribute to the Micrascan's ability to scan the exposure field at high speeds
with no substantial loss of resolution, thereby increasing the throughput
capability of the machine.*
The Company believes that the photolithography exposure equipment market
is one of the largest segments of the semiconductor processing equipment
industry and that SVGL's Micrascan family of photolithography systems are
currently the most technically advanced step-and-scan machines shipping in
multiple quantities to global semiconductor manufacturers.* Micrascan II+
systems capable of printing .30 micron line widths sell for up to approximately
$5,300,000, depending upon configuration. The Micrascan QML lamp-based systems
and Micrascan III laser-based systems, each capable of printing .25 micron line
widths, sell for up to approximately $7,200,000, depending upon configuration.
Uncertain Market for Micrascan Products. To address the market for
advanced photolithography exposure systems, the Company has invested and expects
to continue to invest substantial resources in SVGL's Micrascan technology and
its family of Micrascan deep ultraviolet ("Deep UV") step and scan
photolithography systems, capable of producing line widths of .25 micron and
below. The development of a market for the Company's Micrascan step and scan
photolithography products will be highly dependent on the continued trend
towards finer line widths in integrated circuits and the ability of other
lithography manufacturers to keep pace with this trend through either enhanced
technologies or improved processes. Lithography manufacturers have been
successful in extending the capability of I-Line steppers which have been
utilized in the fabrication of complex semiconductor devices with line widths of
less than 0.5 micron, such as 64 megabit DRAMs. The Company believes Deep UV
lithography will be required to fabricate devices with line widths below 0.3
micron.* Semiconductor manufacturers can purchase Deep UV steppers to produce
product at .25 micron line widths. However, the Company believes that as devices
increase in complexity and size and require finer line widths, the technical
advantages of Deep UV step and scan systems as compared to Deep UV steppers will
enable semiconductor manufacturers to achieve finer line widths with improved
critical dimension control which will result in higher yields of faster
devices.* The Company also believes that the transition to Deep UV step and scan
systems will accelerate in calendar 1998 and that advanced semiconductor
manufacturers are beginning to require volume quantities of production equipment
as advanced as the current and pending versions of Micrascan.* Currently,
competitive Deep UV step and scan equipment capable of producing .25 micron line
widths is available in limited quantities from two competitors, and the Company
believes that at least one other manufacturer of advanced photolithography
systems will begin limited shipments of step and scan machines in the near
future.* There can be no assurance that the Company will be successful in
competing with such systems.* Further, if manufacturers of I-Line or Deep UV
steppers are able to further enhance existing technology to achieve finer line
widths sufficiently to erode the competitive and technological advantages of
Deep UV step and scan systems, demand for the Micrascan technology may not
develop as the Company expects.*
The Company believes that advanced logic devices and DRAMs will require
increasingly finer line widths.* Consequently, SVGL must continue to develop
advanced technology equipment capable of meeting its customers' current and
future requirements while offering those customers a progressively lower cost of
ownership.* In particular, the Company believes that it must continue its
development of future systems capable of printing line widths finer than .25
micron and processing 300mm wafers.*
The Company believes that for SVGL to succeed in the long term, it must sell
its Micrascan products on a global basis. The Japanese and Pacific Rim markets
(including fabrication plants located in other parts of the world which are
operated by Japanese and Pacific Rim semiconductor manufacturers) represent a
substantial portion of the overall market for photolithography exposure
equipment. To date, the Company has not been successful penetrating either of
these markets. (See "Importance of the Japanese and Pacific Rim Markets".) |
